Airplane with retractable landing gear



Nov. 19, 1940. J. o. RUSH I AIRPLANE WITH RETRACTABLE LANDING GEAR Filed Sept. 26, 1939 2 Sheets-Sheet 1 Fig] M QM w 5 mo w m 0 H fi Q 0,

Afforney Nov. 19, 1940, J. o. RUSH I 2,222,376

AIRPLANE WITH RETRACTABLE LANDING GEAR Filed Sept. 26, 1959 2 Sheets-Sheet 2 Patented Nov. 19, 1940 PATET OFFICE 2,222,376 AIRPLANE WITH RETRACTABLE LANDING GEAR John Osgood Rush, Mobile, Ala. Application September 26, 1939, Serial No. 296,679

'8 Claims. (01. 244-102) This invention relates to airplanes with retractable landing gear and particularly to means for disposing a landing member during flight in a manner to reduce parasitic resistance.

Landing members must naturally be designed for efficient contact with the supporting medium, land or water, but the characteristics which are valuable in this connection are disadvantageous as regards air resistance' Thus in the case of the land plane the landing wheels ofier considerable resistance during flight and the same applies to the floats or pontoons of the seaplane.

In the case of the land plane the landing wheels, for the purpose of reducing resistance, are frequently provided with streamlined hoods which leave only the bottoms of the wheels exposed, and in the case of the seaplane the top portions of the floats or pontoons are ordinarily streamlined. In each case the bottom portions of the landing members still offer undesirable resistance during flight. According to the present invention I overcome this difiiculty by providing wing cavities for the reception of the landing members and during retraction of the landing gear-I invert them so that when received in the cavities only their fair portions, shaped to reduce air resistance, are exposed.

In the accompanying drawings I have shown the invention, by way of example, as applied to a hydro-airplane in connection with its tip floats and I shall proceed with the description with ref- "ere'nce to these drawings in which-- Figure 1 shows in front elevation a's'eaplane and a tip float in accordance with the present invention, the float being shown in extended relation.

Figure 2 shows, on an enlarged scale, the tip float, partly in elevation and partly in section, and the lower portion of a float strut in longitudinal section.

Figure 3 shows the parts in Figure 2 as seen from the left of that figure, the float being broken away and the strut being shown-in section on a plane at right angles to the section plane of Figure 2.

Figure 4 is a partial view of the devices of Figure 1, enlarged, showing the float in fully retracted position.

Figure 5 is a section substantially on line XX of Figures 1 and 4, and

' Figure 6 is a wiring diagram for an operating motor and certain locking mechanisms for positively securing the float in extended and retracted positions.

Referring to the drawings, reference character H, Figure l, designates the hull of -a flyi 4 boat, and reference numeral W a wing of the latter. A hollow strut I7 is pivoted to the wing at the point Mr on a fore and aft axis. A bell crank lever 8 comprises the link portions 8a and 5 8b of which the former is pivoted to the strut ll on an axis 80, parallel to the axis l'lsc, within the strut. Clearance for portion 8a is provided by a slot Ha in the inboard side of the strut. At the juncture of portions 8a and 8b the bell crank 10 lever B is pivoted to one end of a link 3| whose other end is pivoted to the wing. The free end .of lever portion 8b is pivoted to a link 32 whose other end in known manner is engaged by a threaded rod disposed in the wing and extending longitudinally of the latter and rotatable by means of a motor. -The drive motor is indicated at Z5,Figure 6.

The lower end of strut I1 is ofiset in the outboard direction to provide a foot portion Mb 20 whose extremity is bifurcated and pivoted to the float It by means of coaxial pins I and la which are parallel tothe axis i'lx.

The float It is of any suitable construction and has a bottom planing surface l6a of V-section and a fair top portion l6b shaped to-reduce air resistance, i. e. streamlined. On its inboard side float I6 is provided with'a recess I50 of complementary form to the foot portion l'lb of the strut. so)

A link 2 is pivoted at its lower-end to float it on a pin 23 supported'in the lower portion of recess I6c. The upper'end of link 2 is passed upwardly through'a suitable passage lie in the foot portion lib, its upper end, in the operative position of parts shown in Figures 1 to 3, extending just beyond a partition plate 20 which is secured transversely ofthe, strut just above the foot portion' llb, plate 20 being' provided with an 0 opening 20a in continuation of the passage He. The upper end of link 2 is provided with a boss 2 i pierced to receive a pin 22 by means of which the link is pivoted to the lower end of a rack 3 which is reciprocable longitudinally of the strut between guides l and la, Figure 3.

Fixed to the lower end of portion 8a of the bell crank lever 8 on the axis 8c is a bevel pinion 9, which pinion need only be partially circumferentially toothed. The .pinion 9 engages cooperating teeth ll formed on a segment III which is pivoted in the strut on an axis Ila at right angles to the axis 80. The segment 10 is provided with gear teeth Illa which enga e a pinion |2a rotatable on a shaft I21: and fixed to a the axis of the pins l and la.

gear He by means of a sleeve l2. The gear.

is in engagement with the rack 3.

The parts are locked in the relation shown in Figures 1 to 3 by means of a pin '6 which passes Solenoid 4, Figure 6, is in a circuit 24 across which are connected the motor 25 and a further solenoid 3|; The latter solenoid has its core piece engaged with one arm 28 of a bell crank lever whose other arm. is operatively engaged with a pin 26 to-retract the latter against a spring 29 and a weight 21, thereby causing a pilot warning 30 to be shown. Circuit 24 is provided with a switch 24a.

Assuming the parts to be in the relation shown in Figures 1 to 3, the closing of switch 24a will start motor 25 and will energize the coils of solenoids 4 and 3|, causing the pins 6 and 26 to be retracted. The retraction of pin 6 releases rack 3 and causes the pilot signal l9 to show. As the float retracting linkage is operated by motor 25, portion 8a of the bell crank lever 8 swings relative to strut I! in the direction of the arrow, Figure 2, as the strut is swung in an inboard direction. Due to the relative swinging of the strut and link 8a, pinion 9 is rotated and through the associated gearing causes rack 3 to be pulled inwardly and through link 2 the float is caused to swing in a clockwise direction about The wing W is provided with a cavity 33 shaped, at least in outline, as the portion of the float l6 below the fair top surface of the latter and a recess 34 extends outwardly from the cavity 33 for the re-' 5 ception of strut II. By the time strut I! has swung into its recess, from position A, through position B, and to position 0, Figure 1, the float has been swung about its hinged connection so that the foot portion l'lb is fully received in so'recess I60, the outer surface of the foot portion lying flush with the fair surface lib and conforming to the contours of the latter. With the float fully received in the cavity 33 only its fair surface is exposed below the wing, this being c1ea'r1y .shown in Figures 4 and 5, and, as also shown in Figure 4, the outer surface of the strut v is flush with the lower surface ofthe wing and preferably conforms to the curvature of the latter.

. so When the float and strut have assumed fullyretracted position switch 24a is opened, thereby stopping motor 25 and de-energizing the coils of solenoids 4 and; 3|. Spring l3 consequently projects pin 3 through an aperture l4 in link 2 as which has come into register with the apertures of guides I and 1a, and the pilot warning is is swung away from the window Isa. Similarly,

pin 26 is projected by spring 29 into an opening formed in a locking plate l5, Figure 2, in the 7 outboard side of the float. The locking relation is indicated in Figure 4. The pilot warning 30 is simultaneously swung out of indicating position. The weights l8 and 21 are provided for the purpose of projecting the locking pins in 75 the case of failure of springs l3 and 29.

To move thefloat to operative position motor 25 is reversed and switch 24a closed, whereupon pins 6 and 26 are retracted, the'strut is swungoutwardly, and the float is swung about its hinged connection relative to the strut until the relation of parts shown in Figures 1 to 3 is resumed. Opening of switch 24a to stop motor 25 will, of course, causepin 26 to take the locking position shown in Figures 2 and 3.

In the event of failure of locking pin 6 the float will still remain fixed in position, since rack 3 cannot move in the absence of operation of motor 25 If pin 22 should fail, inboard rocking of the float is still prevented by the rack, and outboard rocking is prevented by the boss 2| of link 2 engaging the margin of opening 20a.

From the above it will be seen that-I have provided means whereby the hydrodynamic portion of the float is removed completely from the air stream whenthe float is retracted and only the streamlined portion is left exposed. It is possible for this inverted float to act as the major portion of an engines streamlining. An inherent featureof this type of float is that as the float retracts, increasing the moment arm of the float assembly with respect to its main -supporting hinge, the center of gravity of the float body moves toward the float assembly main supporting hinge, thereby reducing the total moment on the said hinge. Another feature of this type of float is that the span of wing surface necessarily cut away for housing the float is materially reduced, this being an important item in stressed-skin wing construction. It will be understood that I do not limit myself to details of form and construction herein disclosed except as in the following claims.

I claim:

1. A hydroairplane comprising a Wing havinga cavity in itslower surface, a float member having a bottom surface designed for efficient water contact and a fair top portion shaped to reduce air resistance, a strut in pivotal connection .with both said wing and said float and adapted to position the float operatively below the wing with its bottom down, means for swinging said strut to retract the float toward and into said cavity, and means for rotating the float during its retraction to inverted position about its pivotal connection with said strut so that its bottom portion is received in said cavity with substantially only said fair portion exposed be- I low said wing. r

2.- Structure according to claim 1 wherein said her is arranged, and wherein the top portion of.

said member has a recess which receives said foot portion when said member is inverted.

3. An airplane comprising a wing having a cavity in its lower surface, a landing member having a bottom portion designed for efiicient contact with a supporting surface and a fair top portion shaped to reduce air resistance, a strut in pivotal connection with both said wing and said member and adapted to position the latter operatively below the wing with its bottom portion down, means for swinging said strut to retract said'membertoward and into said cavity, said swinging means comprising a link portion pivoted to said strut and swinging relative to the latter during the retracting operation, a link pivoted to said member at one end and .having its upper end guided for reciprocation by said strut, and means for inverting said member during its retraction so that its bottom portion is received in said cavity with substantially only said botton portion exposed below the wing, said inverting means including a gearing train between said link and said link portion whereby the said relative swinging of the latter is translated into a longitudinal movement of said link.

4. An airplane comprising a wing having a cavity in its lower surface, a landing member having a bottom portion designed for efficient contact with a supporting surface and a fair top portion shaped to reduce air resistance, a strut in pivotal connection at one end with said wing and having at its other end an angular foot portion whose extremity is in pivotal connection with said member, means for swinging said strutto retract said member toward and into said cavity, said swinging means comprising a link portion pivoted to said'strut and swinging relative to the latter during the retracting operation, a rack reciprocable longitudinally of said strut, a link connecting said rack and said member, and means for inverting said member during its retraction so that its bottom'portion is received in said cavity withsubstantially only said bottom portion exposed below the wing, said inverting means including a gear fixed to said link portion on its axis of pivotal connection with said strut and a connection betweenvsaid gear and said rack whereby rotation of said gear as a result of the said relative swinging of said link portion is transmitted, to said rack to impart longitudinal movement to the latter. 5. A hydroairplane comprising a wing havin a cavity in its lower surface, a float having a bottom surface designed for eflicient water contact and a fair top portion shaped to reduce air resistance, means connecting said wing and said float for operatively positioning the latter below the wing with the bottom down, means for retracting said float toward and into said cavity, and means for inverting said float during its retraction so that its bottom pgrtion is received in said cavity with substantially only said fair portion exposed below the wing.

6. A hydroairplane comprising a wing having a cavity in its lower surface, a float having a bottom surface designed for efiicient water con-' tact and a fair top portion shaped to reduce air resistance, a strut in pivotal connection with both said wing and said float and adapted to position the float operatively below the wing with its bottom down, means for swinging said strut to retract the float-toward and into said cavity, means for rotating the float during its retraction to inverted position about its pivotal connection with said strut so that its bottom portion is received in said cavity with substantially only said fair portion exposed below said wing, and means independent of said swinging means for locking said float in its operative and retracted positions.

7. Structure according to claim 1 wherein said strut has an angular foot portion at whose extremity the pivotal connection with said member is arranged, and wherein the top portion of said member has a recess which receives said foot portion when said member is inverted, said foot portion having a surface forming a part of the fair surface of said member when said foot portion is fully received in said recess. I

8. Structure according to claim 1 wherein said strut has an angular foot portion at whose extremity the pivotal connection with said member is arranged, wherein'the top portion of said member has a recess which receives said foot portion when said member is inverted, said foot portion having a surface forming a part of the fair surface of said member when said foot portion is fully received in said recess, and wherein said wing is provided with a recess which receives the strut with the exception of its foot portion when said member is fully retracted, said strut when so received having an exposed surface conformed to the lower surface of the wing.

JOHN OSGOOD RUSH. 

